text: /*
   * linux/arch/ppc/kernel/traps.c
   *
   * Copyright (C) 1995-1996  Gary Thomas (gdt@linuxppc.org)
   *
   * Modified by Cort Dougan (cort@cs.nmt.edu)
   * and Paul Mackerras (paulus@cs.anu.edu.au)
   * fixed Machine Check Reasons by Reinhard Meyer (r.meyer@emk-elektronik.de)
   *
   * (C) Copyright 2000-2003
   * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   *
   * See file CREDITS for list of people who contributed to this
   * project.
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License as
   * published by the Free Software Foundation; either version 2 of
   * the License, or (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
   * MA 02111-1307 USA
   */
  
  /*
   * This file handles the architecture-dependent parts of hardware exceptions
   */
  
  #include <common.h>
  #include <command.h>
  #include <asm/processor.h>
  
  #if (CONFIG_COMMANDS & CFG_CMD_KGDB)
  int (*debugger_exception_handler) (struct pt_regs *) = 0;
  #endif
  
  /* Returns 0 if exception not found and fixup otherwise.  */
  extern unsigned long search_exception_table (unsigned long);
  
  /* THIS NEEDS CHANGING to use the board info structure.
  */
  #define END_OF_MEM      0x02000000
  
  /*
   * Trap & Exception support
   */
  
  void print_backtrace (unsigned long *sp)
  {
  	int cnt = 0;
  	unsigned long i;
  
  	printf ("Call backtrace: ");
  	while (sp) {
  		if ((uint) sp > END_OF_MEM)
  			break;
  
  		i = sp[1];
  		if (cnt++ % 7 == 0)
  			printf ("\n");
  		printf ("%08lX ", i);
  		if (cnt > 32)
  			break;
  		sp = (unsigned long *) *sp;
  	}
  	printf ("\n");
  }
  
  void show_regs (struct pt_regs *regs)
  {
  	int i;
  
  	printf ("NIP: %08lX XER: %08lX LR: %08lX REGS: %p TRAP: %04lx DAR: %08lX\n",
  		regs->nip, regs->xer, regs->link, regs, regs->trap, regs->dar);
  	printf ("MSR: %08lx EE: %01x PR: %01x FP: %01x ME: %01x IR/DR: %01x%01x\n",
  		regs->msr,
  		regs->msr & MSR_EE ? 1 : 0, regs->msr & MSR_PR ? 1 : 0,
  		regs->msr & MSR_FP ? 1 : 0, regs->msr & MSR_ME ? 1 : 0,
  		regs->msr & MSR_IR ? 1 : 0, regs->msr & MSR_DR ? 1 : 0);
  
  	printf ("\n");
  	for (i = 0; i < 32; i++) {
  		if ((i % 8) == 0) {
  			printf ("GPR%02d: ", i);
  		}
  
  		printf ("%08lX ", regs->gpr[i]);
  		if ((i % 8) == 7) {
  			printf ("\n");
  		}
  	}
  }
  
  
  void _exception (int signr, struct pt_regs *regs)
  {
  	show_regs (regs);
  	print_backtrace ((unsigned long *) regs->gpr[1]);
  	panic ("Exception in kernel pc %lx signal %d", regs->nip, signr);
  }
  
  void MachineCheckException (struct pt_regs *regs)
  {
  	unsigned long fixup;
  
  	/* Probing PCI using config cycles cause this exception
  	 * when a device is not present.  Catch it and return to
  	 * the PCI exception handler.
  	 */
  	if ((fixup = search_exception_table (regs->nip)) != 0) {
  		regs->nip = fixup;
  		return;
  	}
  #if (CONFIG_COMMANDS & CFG_CMD_KGDB)
  	if (debugger_exception_handler
  	    && (*debugger_exception_handler) (regs))
  		return;
  #endif
  
  	printf ("Machine check in kernel mode.\n");
  	printf ("Caused by (from msr): ");
  	printf ("regs %p ", regs);
  	/* refer to 603e Manual (MPC603EUM/AD), chapter 4.5.2.1 */
  	switch (regs->msr & 0x000F0000) {
  	case (0x80000000 >> 12):
  		printf ("Machine check signal - probably due to mm fault\n"
  			"with mmu off\n");
  		break;
  	case (0x80000000 >> 13):
  		printf ("Transfer error ack signal\n");
  		break;
  	case (0x80000000 >> 14):
  		printf ("Data parity signal\n");
  		break;
  	case (0x80000000 >> 15):
  		printf ("Address parity signal\n");
  		break;
  	default:
  		printf ("Unknown values in msr\n");
  	}
  	show_regs (regs);
  	print_backtrace ((unsigned long *) regs->gpr[1]);
  	panic ("machine check");
  }
  
  void AlignmentException (struct pt_regs *regs)
  {
  #if (CONFIG_COMMANDS & CFG_CMD_KGDB)
  	if (debugger_exception_handler
  	    && (*debugger_exception_handler) (regs))
  		return;
  #endif
  	show_regs (regs);
  	print_backtrace ((unsigned long *) regs->gpr[1]);
  	panic ("Alignment Exception");
  }
  
  void ProgramCheckException (struct pt_regs *regs)
  {
  #if (CONFIG_COMMANDS & CFG_CMD_KGDB)
  	if (debugger_exception_handler
  	    && (*debugger_exception_handler) (regs))
  		return;
  #endif
  	show_regs (regs);
  	print_backtrace ((unsigned long *) regs->gpr[1]);
  	panic ("Program Check Exception");
  }
  
  void SoftEmuException (struct pt_regs *regs)
  {
  #if (CONFIG_COMMANDS & CFG_CMD_KGDB)
  	if (debugger_exception_handler
  	    && (*debugger_exception_handler) (regs))
  		return;
  #endif
  	show_regs (regs);
  	print_backtrace ((unsigned long *) regs->gpr[1]);
  	panic ("Software Emulation Exception");
  }
  
  
  void UnknownException (struct pt_regs *regs)
  {
  #if (CONFIG_COMMANDS & CFG_CMD_KGDB)
  	if (debugger_exception_handler
  	    && (*debugger_exception_handler) (regs))
  		return;
  #endif
  	printf ("Bad trap at PC: %lx, SR: %lx, vector=%lx\n",
  		regs->nip, regs->msr, regs->trap);
  	_exception (0, regs);
  }
  
  #if (CONFIG_COMMANDS & CFG_CMD_BEDBUG)
  extern void do_bedbug_breakpoint (struct pt_regs *);
  #endif
  
  void DebugException (struct pt_regs *regs)
  {
  
  	printf ("Debugger trap at @ %lx\n", regs->nip);
  	show_regs (regs);
  #if (CONFIG_COMMANDS & CFG_CMD_BEDBUG)
  	do_bedbug_breakpoint (regs);
  #endif
  }
  
  /* Probe an address by reading.  If not present, return -1, otherwise
   * return 0.
   */
  int addr_probe (uint * addr)
  {
  #if 0
  	int retval;
  
  	__asm__ __volatile__ ("1: lwz %0,0(%1)\n"
  			      "   eieio\n"
  			      "   li %0,0\n"
  			      "2:\n"
  			      ".section .fixup,\"ax\"\n"
  			      "3: li %0,-1\n"
  			      "   b 2b\n"
  			      ".section __ex_table,\"a\"\n"
  			      "   .align 2\n"
  			      "   .long 1b,3b\n"
  			      ".text":"=r" (retval):"r" (addr));
  
  	return (retval);
  #endif
  	return 0;
  }
  